30 St Mary Axe (widely known informally as The Gherkin and previously as the Swiss Re Building) is a commercial skyscraper in London's primary financial district, the City of London. It was completed in December 2003 and opened in April 2004.[4] With 41 storeys, it is 180 metres (591 ft) tall[3] and stands on the former site of the Baltic Exchange, which was extensively damaged in 1992 by the explosion of a bomb placed by the Provisional IRA in St Mary Axe, the street from which the tower takes its name.[4][9]

Contents

History[edit]

Site[edit]

The building stands on the former site of the Baltic Exchange, the headquarters of a global marketplace for ship sales and shipping information. On 10 April 1992 the Provisional IRAdetonated a bomb close to the Exchange, causing extensive damage to the historic building and neighbouring structures.[4][9]

After English Heritage later discovered the damage was far more severe than initially thought, they stopped insisting on full restoration, albeit over the objections of the architectural conservationists who favoured reconstruction.[14] The Baltic Exchange sold the land to Trafalgar House in 1995.[15] Most of the remaining structures on the site were then carefully dismantled, the interior of Exchange Hall and the façade were preserved, hoping for a reconstruction of the building in the future.[15] The architectural salvage, its eventual sale for £800,000 and move to Tallinn, Estonia, awaiting reconstruction as the centrepiece of the city's commercial sector, can be seen in the Baltic Exchange listing.

In 1996, Trafalgar House submitted plans for the Millennium Tower, a 386-metre (1,266 ft) building with more than 140,000 m2 (1,500,000 sq ft) of office space, apartments, shops, restaurants and gardens. This plan was dropped after objections for being totally out-of-scale with the City of London and anticipated disruption to flight paths for both London City and London Heathrow airports; the revised plan for a lower tower was accepted.

The tower's topmost panoramic dome, known as the "lens", recalls the iconic glass dome that covered part of the ground floor of the Baltic Exchange.[4]

The Gherkin name was applied to the current building at least as far back as 1999, referring to that plan's highly unorthodox layout and appearance.[16]

Planning process[edit]

On 23 August 2000, Deputy Prime MinisterJohn Prescott granted planning permission to construct a building much larger than the old Exchange on the site.[12] The site was special because it needed development, was not on any of the "sight lines" (planning guidance requires that new buildings do not obstruct or detract from the view of St Paul's dome when viewed from a number of locations around London), and it had housed the Baltic Exchange.

The plan for the site was to reconstruct the Baltic Exchange. GMW Architects proposed a new rectangular building surrounding a restored exchange—the square shape would have the type of large floor plan that banks liked. Eventually, the planners realised that the exchange was not recoverable, forcing them to relax their building constraints; they hinted that an "architecturally significant" building might obtain a favourable reception from city authorities. This gave the architect a free hand in the design; it eliminated the restrictive demands for a large, capital-efficient, money-making building, whose design was per the client's desire.[17]

Swiss Re's low level plan met the planning authority's desire to maintain London's traditional streetscape with its relatively narrow streets. The mass of the Swiss Re tower was not too imposing. Like Barclays Bank's former City headquarters in Lombard Street, the idea was that the passer-by in neighbouring streets would be nearly oblivious to the tower's existence until directly underneath it.

Design and construction[edit]

The building was constructed by Skanska, completed in December 2003 and opened on 28 April 2004.[4] The primary occupant of the building is Swiss Re, a global reinsurance company, which had the building commissioned as the head office for its UK operation. The tower is thus sometimes known as the Swiss Re Building, although this name has never been official and has more recently fallen out of favour since the company's main headquarters is in Zurich and the Gherkin name has become more popular.[18]

30 St Mary Axe under construction

The building uses energy-saving methods which allow it to use half the power that a similar tower would typically consume.[18] Gaps in each floor create six shafts that serve as a natural ventilation system for the entire building even though required firebreaks on every sixth floor interrupt the "chimney." The shafts create a giant double glazing effect; air is sandwiched between two layers of glazing and insulates the office space inside.[4]

Architects promote double glazing in residential houses to avoid the inefficient convection of heat, but the tower exploits this effect. The shafts pull warm air out of the building during the summer and warm the building in the winter using passive solar heating. The shafts also allow sunlight to pass through the building, making the work environment more pleasing, and keeping the lighting costs down.

The primary methods for controlling wind-excited sways are to increase the stiffness, or increase damping with tuned/active mass dampers. To a design by Arup, its fully triangulated perimeter structure makes the building sufficiently stiff without any extra reinforcements. Despite its overall curved glass shape, there is only one piece of curved glass on the building—the lens-shaped cap at the very top.[4]

On the building's top level (the 40th floor), there is a bar for tenants and their guests featuring a 360° view of London. A restaurant operates on the 39th floor, and private dining rooms on the 38th.[18] Whereas most buildings have extensive lift equipment on the roof of the building, this was not possible for the Gherkin, since a bar had been planned for the 40th floor. The architects dealt with this by having the main lift only reach the 34th floor, and then having a push-from-below lift to the 39th floor. There is a marble stairwell and a disabled persons' lift which leads the visitor up to the bar in the dome.

The building is visible over long distances: from the north, for instance, it can be seen from the M11 motorway, some 32 kilometres (20 mi) away,[18][19] while to the west it can be seen from the statue of George III in Windsor Great Park.

After completion[edit]

In April 2005, the press reported that a glass panel two-thirds up the tower had fallen to the plaza beneath. The plaza was sealed off but the building remained open. A temporary covered walkway, extending across the plaza to the building's reception, was erected to protect visitors. Engineers examined the other 744 glass panels on the building.[20] The cost of repair was covered by main contractor Skanska and curtain-wall supplier Schmidlin (now called Schmidlin-TSK AG).[18]

In September 2006, the building was put up for sale with a price tag of £600 million.[26] Potential buyers included British Land, Land Securities, Prudential, ING, and the Abu Dhabi royal family. On 21 February 2007, IVG Immobilien AG and UK investment firm Evans Randall completed their joint purchase of the building for £630 million, making it Britain's most expensive office building.[27][28] Swiss Re booked a gain of more than £300 million from the sale.[29] The new owners are seeking compensation from four of their former managers on the deal, in which about £620 million was paid for a building with a build cost of about £200 million, giving the previous owners a clear £300 million profit.[30]

Since February 2010,[31]Sky News has broadcast its flagship business programme, Jeff Randall Live, from a studio in the building. In addition the top two floors of tower are now available on a private hire basis for events.[32]

Deloitte announced in April 2014 that the building was again being put up for sale, with an expected price of £550 million.[33] The current owners could not afford to make loan repayments, citing differences in the value of the multi-currency loan and the British pound, high interest rates and general financing structure.[34]

Gallery[edit]

Start of steelwork, December 2001, pictured from Undershaft

Inside the building, on the top floor

Upper portion of the building with the skyscrapers of Canary Wharf in the background